Low nickel loading carbon microfibers fabricated by electrospinning for the glycerol electrooxidation coupled with the continuous gas-phase CO2 reduction reaction towards formate

The glycerol market is currently experiencing a surplus due to increased biodiesel production,mcreating a demand for innovative approaches for its optimal utilization. Electrochemical valorization, particularly electro-oxidation, emerges as a promising solution for transforming excess glycerol into valuable products. Here, we report the use of carbon microfibers with ultralow nickel content (<5 wt %) to catalyze glycerol oxidation reaction (GOR), coupled with continuous gas-phase CO2 electroreduction to obtain formate. The humidified CO2-fed membrane electrode assembly electrolyzer, devoid of noble metals, efficiently produces oxidized products like lactate at concentrations of 0.144 g L-1 from glycerol and formate solutions reaching up to 100 g L-1 from CO2, surpassing previous methods employing commercial Pt-based materials. This novel approach not only enhances glycerol conversion efficiency but also contributes to sustainable carbon utilization, leading to the production of value added products.

The authors gratefully acknowledge financial support through projects PID2019-108136RB-C31 (MCIN/AEI/10.13039/501100011033), PID2022-138491OB-C31 (MICIU/AEI/10.13039/501100011033 and ERDF/EU), TED2021–129810B-C21 (MCIN/AEI/10.13039/501100011033 and European Union Next Generation EU/PRTR), PLEC2022-009398 (MCIN/AEI/10.13039/501100011033 and European Union Next Generation EU/PRTR), PCI2024-155027-2 (MICIU/AEI/10.13039/501100011033/UE) and the “Complementary Plan in the area of Energy and Renewable Hydrogen” funded by Autonomous Community of Cantabria, Spain, and the European Union Next Generation EU/PRTR. The present work is related to CAPTUS Project. This project has received funding from the European Union's Horizon Europe research and innovation programme under grant agreement No 101118265. We are also grateful for the Bi carbon-supported nanoparticles prepared and provided by the group of Prof. V. Montiel and Dr. José Solla-Gullón from the Institute of Electrochemistry of the University of Alicante.